口服人α干扰素转化双歧杆菌促进小鼠淋巴细胞的增殖和成熟

Intragastric administration of interferon-α-transformed Bifidobacterium promotes lymphocyte proliferation and maturation in mice

目的探讨人α干扰素(IFN-α)基因转化双歧杆菌口服后对小鼠免疫功能的调节作用。方法构建含人IFN-α基因的大肠杆菌-双歧杆菌穿梭表达载体p BADX-h IFNα2b,电转化获得IFN-α基因转化双歧杆菌,收集L-阿拉伯糖诱导h IFN-α2b表达后的菌体制备成活菌悬液,灌胃Balb/C小鼠。实验组(IFN)小鼠用0.2%L-阿拉伯糖诱导表达后的h IFN-α2b转化双歧杆菌处理,每只按0.1 ml 1010/ml活菌灌胃;阴性对照组(NC)用等量等体积空载体p BADX转化双歧杆菌活菌灌胃;空白对照组(BC)用等体积生理盐水灌胃。隔天灌胃1次,连续处理2周。流式细胞术检测小鼠胸腺、脾脏和血液中淋巴细胞亚群和比例,流式试剂盒检测IFN-γ、IL-4等免疫因子的含量。结果与NS组和BC组相比,IFN组小鼠胸腺CD3+CD8+、CD4+CD8+细胞的比例显著升高(P<0.01);脾脏CD3+CD4+、CD3+CD8+和CD4+CD8+细胞的比例均显著升高(P<0.01);血液中只有CD3+CD8+细胞的比例显著升高(P<0.01)。血液中IFN组IFN-γ的含量比BC组和NS组显著升高(P<0.01);此外,NS组IFN-γ的含量比BC组显著升高(P<0.05);3组小鼠中血液h IFN-α2b和IL-4的浓度无显著性差异(P>0.05)。结论口服h IFN-α转化的双歧杆菌促进小鼠胸腺和脾脏淋巴细胞增殖和成熟,增高血液Th1类细胞因子水平。

Objective To investigate the effects of intragastric administration of human interferon- α（h IFN- α）- transformed Bifidobacterium on immune functions of mice. Methods The E.coli- Bifidobacterium shuttle expression vector containing h IFN- αgene was constructed and transformed into Bifidobacterium. The h IFN-α-transformed Bifidobacterium suspension（1010/ml） was prepared after induction with 0.2% L-arabinose for h IFN-α expression and administered intragastrically in male Balb/C mice at the dose of 0.1 ml every other day for 2 weeks, with the mice receiving empty vector- transformed Bifidobacteria as the negative control and those having an equal volume of saline as the blank control. The percentages of mononuclear cell subsets in the thymus, spleen and blood were detected in the mice by flow cytometry, and the serum levels of IL-4, IL-12, IFN-γ and TNF-α were assayed using mouse cytokine Flow Cytomix Kit. Results The percentages of CD3＋CD8^＋and CD4^＋CD8^＋cells in the thymus, CD3^＋CD4^＋, CD3^＋CD8^＋and CD4^＋CD8^＋cells in the spleen, and CD3^＋CD8^＋cells in the blood all increased significantly in IFN group as compared with those in the negative and blank control groups（P〈0.01 or 0.05）. The serum level of IFN- γ also increased significantly（P〈0.05） while IL- 4 level remained unchanged in IFN group compared with those in the two groups.Conclusion Intragastric administration of h IFN- α- transformed Bifidobacterium promotes lymphocyte proliferation and maturation and increases the serum levels of Th1 cytokines in mice.